Augustus h



(ModeL) A. H. PALMER.

Switch for Tel-ephone Exchanges. No. 238,803. Patented March 15,1881

WITNESSES: INVENTDR;

N. PETERS PKOTO-LITHQGRAPHEH, WASHINGTON, D O.

P TENT Price.

AUGUSTUS H. PALMER,

OF UTIGA, NEW YORK.

SWITCH FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming part of Letters Patent No. 238,803, dated March15, 1881. Application filed June 28, 1880. (ModeL) 'and the letters ofreference marked thereon.

Figure l is a sectional view, showing my device attached to theswitch-board. Fig. ll is a rear view, showing the parts in contact withthe ground-wire. Fig. Ill is a view showing the ground-connection brokenwith the plug or connector inserted. Fig. IV is a sectional view of myimproved plug or connecting-pin.

This invention relates to an improvement in electric switches anddevices for operating; the same, and is constructed with specialreference to communications by telephone where several instruments arearranged upon the same circuit or several circuits centering at a singlepoint, the object being to receive a call from one instrument at thecentral office for communication with a second instrument, and so as tocall that instrument and then put the two in communication and theinvention consists in the construction, as hereinafterdescribed, andparticularly recited in the claims.

A represents the switch-board into which any desired number of cases, B,are inserted,

- and secured by means of a central screw-bolt,

0, not D, and copper washers a and a. The operating-parts of the switchare inclosed within the case B, and by this means are protented fromdirt and dust and not so liable to be clogged up.

In any opening on one side of the case B is inserted a tube or packing,f, of vulcanite or other suitableinsulating material, E, in to which issecured a female screw, b, with a platina point, I), secured in itsinner end, and the outer end of which receives the male screw F by whichthe ground-wire is attached. By this simple device any size of wire canbe connected to the case without disturbing the platina point, (see Fig.III,) which makes this style or mode of connection very reliable.

Instead of a female screw a bushing may be inserted in the vulcanite Bwith a platina point, and instead of the male screw a plug may be usedwithout departing from the spirit of my invention.

G is ajack or dog pivoted in the case at c, and is provided with twoshort arms or logs, o and c, and one long arm or lug, jl The long arm orlug is provided with a platina point at d, which, when aground-connection is on, rests against the platina point b in the femalescrew 1), (see Fig. Ill.) and is kept there by the force exerted on thelong arm by the spiral spring H. This spring, being placed at the outerend of the long arm or lug f, exerts more power in retaining said arm incontact with the groundline than if placed at any other point on thearm, thus forming a flexible, positive, and reliable connection. Thelugs e and e are located so as to project slightlyover the holes 9 and gin the case B, so that when the pin or.c0nmeeting-plug I is inserted ineither hole it will come in immediate contact with the lug and thearinfwill be thrown back, thus cutting ofi the ground, and at the sametime the lug 6 will be thrown in contact with the wall of the case B atthe point x, and connection made.

The plug or connecting-pin I is slitted, as shown in Figs. Ill and 1V,so as to make the point elastic and less liable to be displaced and moreeasy of insertion. It may, however, also be made solid. The outerend orshank of pin 1 has a tip of vulcanite or other insulating materialattached thereto, and is also screw-threaded to receive the nut h, andalso to enable it to be securely attached to the handle K, which is alsomade of y 'ulcanite or other insulating material.

The parts J and K are cut out so as to form a cavity, 71 to receive thenut h, washer l, and wire L, the said wire being secured to the shank ofthe pin I by simply bending the end around the same and tightening upthe not It against the wire. A hole is made in the tip J to receive thewire through the side thereof instead of at the end, as in the oldstyle,which is liable to be twisted, broken, or worn out very fast.

The operation of my device is as follows: The cases B to any desirednumber, according to the number of subscribers, are secured in theswitch-board a at the central or other exchange, and are connected withwires or other suitable means to current or charged wires. (Not shown.)The device or devices are then in the condition shown in Fig. II, withthe ground on. A call is made to the central or 5 other exchange by asubscriber, as is well understood,which is answered by the attendant.The wishes of the calling subscriber having been made known to him, andthe connection he wishes to be made, the attendant inserts to the pin orplug in the case answering to the order made for communicating-say withW- and then inserts the pin or plug attached tothe other end of theshort or switching wire into the case of the party calling. The ground15 is thereby cut off in both, as shown in Fig. III, and an electriccurrent established between the two subscribers. When the pins or plugsare removed the jack or dogs are thrown back by the force of the springsand a ground cur- 2o rent resumed.

Having thus described my invention, what I claim, and desire to secureby Letters Patcut, is--- i 1. The combination of the perforated case Band pin I with the pivoted dog G and male 25 and female screws 1) and F,arranged in the manner and for the purpose set forth.

2. The jack or dog G, provided with the Y arms or lugs e and e and armf, and contactpoints I) and d,in combination with the plug or 0 plugs I,whereby the ground is cut off and an electric circuit established, asset forth.

3. Thepin or plug I, constructed as described, in combination with thewashers Z, nut h, and wire L, whereby the wire is admitted through 5 theside of the plug-handle and a simple and reliable connection made.

A. H. PALMER.

WVitnesses CHARLES A. RoLFE, CHARLES E. SPAFARD.

